JNTU Kakinada B-Tech 2-1 R1621023 BASIC ELECTRONICS AND DEVICES R16 May 2018 Question Paper

Code No: R1621023
II B. Tech I Semester Supplementary Examinations, May – 2018
BASIC ELECTRONICS AND DEVICES (Electrical and Electronics Engineering)Time: 3 hours Max. Marks: 70
Note: 1. Question Paper consists of two parts (Part-A and Part-B) 2. Answer ALL the question in Part-A
3. Answer any FOUR Questions from Part-B
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PART ?A
1. a)Draw the energy band diagram of an insulator, conductor and semiconductors (3M)
b)Draw the symbol of a varactor diode and mention its applications. (2M)
c)Compare the performance of all rectifiers. (3M)
d)Draw the hybrid model of a transistor. (2M)
e)Mention the relation between the parameters of FET. (2M)
f)What is Barkausan criteria? (2M)
PART ?B
2. a) Derive an expression for conductivity in a intrinsic semiconductor in terms of
electron & hole concentration (7M)
b) Find the concentration of holes & electrons in the P-type silicon at 300
0
K
assuming its resistivity as 0.02?-cm, ?
p
=475cm
2
/vs , ?
i
=1.45?10
10
/cm
3
. (7M)
3. a) Explain the tunneling mechanism with the suitable energy band diagrams in
tunnel diode (10M)
b) Explain V-I characteristics of Zener diode. (M)
4. a) Write a neat diagram and explain working principle of full wave bridge
rectifier (7M)
b) List the types of filters used in rectification & compare various filter circuits in
terms of ripple factors. (7M)
5. a) What is the need for biasing? Explain the types of biasing techniques with neat
circuit diagrams? (7M)
b) What is the condition for avoiding thermal runaway problem? (7M)
6. a) Explain working of two transistor model of an SCR and Draw the SCR
Characteristics (10M)
b) Differentiate between JFET and MOSFET (4M)
7. a)Draw the block diagram of a ?ve feed back system and explain. (4M)
b)Mention the advantages of a negative feedback system and derive them. (10M)

1 of 1
SET – 1
R16